Resonating gas seismic source

Abstract

An apparatus includes a marine seismic source having a volume of gas and a gas reservoir, and the marine seismic source and the gas reservoir are coupled to permit a resonating gas flow to pass therebetween. The apparatus may be a component of a marine seismic survey system. The apparatus may be utilized in a method of marine seismic surveying.

The invention claimed is: 
     
       1. An apparatus, comprising:
 a marine seismic source that includes
 a structural member that defines a perimeter, a first side, and a second side opposite the first side; 
 a port defined through the perimeter of the structural member; 
 a first disc coupled on the first side of the structural member; 
 a second disc coupled on the second side of the structural member; 
 a cavity defined within the structural member between the first and second discs, the cavity contains a volume of gas; 
 an electromechanical device configured to selectively deflect the first disc in response to an input of electrical energy at a frequency; and 
 a conduit that defines a first end and a second end, the conduit coupled to the port on the first end; 
 
 a gas reservoir disposed external to the cavity, the gas reservoir coupled to the second end of the conduit; 
 wherein the conduit is configured to flow at least a portion of the volume of gas within the cavity back and forth between the cavity and the gas reservoir responsive to deflection of the first disc. 
 
     
     
       2. The apparatus of  claim 1 , wherein the frequency of the electrical energy is a resonant frequency of the cavity and conduit combination. 
     
     
       3. The apparatus of  claim 1 , wherein the electromechanical device is configured to deflect the second disc in response to the input of electric energy. 
     
     
       4. The apparatus of  claim 1 , wherein the electromechanical device includes a piezoelectric component. 
     
     
       5. The apparatus of  claim 1 , further comprising a plurality of conduits arranged in an array, the plurality of conduits fluidly couple the cavity to the gas reservoir. 
     
     
       6. The apparatus of  claim 1 , wherein the discs are configured to create a sound pressure level of 200 decibels (dB) relative to a reference pressure of 1 micropascal, and wherein the frequency between and including 1 Hz to 10 Hz. 
     
     
       7. The apparatus of  claim 1 , wherein the frequency is 3 Hz. 
     
     
       8. The apparatus of  claim 1 , wherein the structural member further comprises a hoop configured to maintain a separation between a pair of piezoelectric components. 
     
     
       9. A system, comprising:
 a vessel; 
 a marine seismic source towable behind the vessel, wherein the marine seismic source includes
 a structural member that defines a perimeter, a first side, and a second side opposite the first side; 
 a port defined through the perimeter of the structural member; 
 a first disc coupled on the first side of the structural member; 
 a second disc coupled on the second side of the structural member; 
 a cavity defined within the structural member between the first and second discs, the cavity contains a volume of gas; 
 an electromechanical device configured to selectively deflect the first disc in response to an input of electrical energy at a frequency; and 
 a conduit coupled to the port on a first end of the conduit; 
 
 an external gas reservoir fluidly coupled to the cavity of the marine seismic source by way of a second send of the conduit; 
 wherein the conduit is configured to provide continuous, two-way fluid communication between the cavity and the external gas reservoir. 
 
     
     
       10. The system of  claim 9 , wherein the electromechanical device of the marine seismic source includes a piezoelectric component. 
     
     
       11. The system of  claim 9 , further comprising:
 a plurality of marine seismic sources, wherein the plurality of marine seismic sources are arranged in a stack assembly. 
 
     
     
       12. The system of  claim 9 , wherein the marine seismic source includes an electrically insulating fluid disposed at least partially around the marine seismic source. 
     
     
       13. The system of  claim 9 , wherein the cavity includes a volume of gas at a pressure greater than a static pressure at a particular water depth. 
     
     
       14. A method, comprising:
 disposing a marine seismic source in a body of water, the marine seismic source defines a cavity; 
 disposing a gas reservoir with the marine seismic source in the body of water, the gas reservoir disposed external to the cavity; 
 wherein the cavity of the marine seismic source contains a first portion of a volume of gas, the first portion of the volume of gas in fluid communication with a second portion of the volume of gas, the second portion of the volume of gas contained in the gas reservoir; 
 actuating the marine seismic source; 
 in response to the marine seismic source actuating, a portion of the volume of gas passing from the marine seismic source and to the gas reservoir. 
 
     
     
       15. The method of  claim 14 , wherein actuating the marine seismic source includes applying voltage to a piezoelectric component. 
     
     
       16. The method of  claim 14 , further comprising:
 towing the marine seismic source in the body of water at a depth of 75 meters or deeper. 
 
     
     
       17. The method of  claim 14 , further comprising:
 the marine seismic source producing acoustic energy at a frequency that is within a range between 1 Hz and 10 Hz, at a transmit voltage response of equal to or above 100 decibels (dB) relative to a reference pressure level of 1 micropascal for a 1 volt drive at 1 meter range. 
 
     
     
       18. The method of  claim 17 , wherein the marine seismic source produces acoustic energy at a frequency of 3 Hz.